Reuvers™ Breathing

The deeper you relax,
the better you perform.

Train your breathing with real-time quality feedback.

Get more oxygen from less air, and train your breathing across its whole range.

Zones indicate your nervous system activation. Green means relaxed, red means stressed.

Free Foundation CourseStart immediatelyDownload the appTry a session

What course participants say

Real-time zones show your nervous system state and give every breath-hold a quality mark. Here's what participants share.

Feedback from participants via WhatsApp and Zoom.

"I can feel the shift from doing to being."

"I sleep better. I rest better."

"I don't need to perform. I can just breathe."

"The holds feel hypnotic. It's meditative."

"My life quality has gone up."

"I feel more energy. I feel warmer."

"Being in a group keeps me accountable."

"I can breathe better in yoga class now."

"This is sustainable. I can do this for life."

"I'm not pushing anymore. I trust the method."

"It feels great to do these breathing exercises every day."

"I ran a marathon. I didn't expect to be able to run a marathon."

"I can feel the shift from doing to being."

"I sleep better. I rest better."

"I don't need to perform. I can just breathe."

"The holds feel hypnotic. It's meditative."

"My life quality has gone up."

"I feel more energy. I feel warmer."

"Being in a group keeps me accountable."

"I can breathe better in yoga class now."

"This is sustainable. I can do this for life."

"I'm not pushing anymore. I trust the method."

"It feels great to do these breathing exercises every day."

"I ran a marathon. I didn't expect to be able to run a marathon."

"I love the program. So much more enjoyable than my old breathing exercises."

"In two days, my breath-holds before and after sleep are so much longer."

"Feather breathing is so relaxing. I feel the difference immediately."

"I learned to sense my breathing response and keep it gentle."

"I can do weight training now without getting winded."

"I used to hyperventilate when speaking. Now I can talk without running out of breath."

"I thought relaxation and performance were opposite. Now I see they're connected."

"I'm learning to relax. I'm not trying to achieve something."

"I expected to learn breathing techniques. But I've exceeded my expectations already."

"This method teaches you to feel. Not just to push numbers."

"Feather breathing feels like a conversation with my body. It's not forced."

"I started at 13 seconds. Now I'm at 30 and climbing."

"I love the program. So much more enjoyable than my old breathing exercises."

"In two days, my breath-holds before and after sleep are so much longer."

"Feather breathing is so relaxing. I feel the difference immediately."

"I learned to sense my breathing response and keep it gentle."

"I can do weight training now without getting winded."

"I used to hyperventilate when speaking. Now I can talk without running out of breath."

"I thought relaxation and performance were opposite. Now I see they're connected."

"I'm learning to relax. I'm not trying to achieve something."

"I expected to learn breathing techniques. But I've exceeded my expectations already."

"This method teaches you to feel. Not just to push numbers."

"Feather breathing feels like a conversation with my body. It's not forced."

"I started at 13 seconds. Now I'm at 30 and climbing."

Individual experiences. Results vary.

Is This For You?

Four reasons to train your breath with zones.

Oxygen Efficiency

More oxygen from less air. Better physical and mental performance.

The Sweet Spot

Relaxed enough to enjoy but strong enough to improve your breathing.

High Stamina

Become more resilient. Handle more with less effort.

Calm Energy

Your nervous system settles. Calm, energized, and ready for the day.

Why train your breath at all? →

The app

It reads your breath and adapts to you

Each round scores your effort and your calm. Stay in the green zone to get more oxygen from less air.

  • It adapts to you

    Every session starts from where your body is today, not where it was last week.

  • Live guidance and scoring

    Cues as you breathe, and a nervous-system score when the round ends.

  • Nothing to wear

    No chest strap, no sensors. Your breathing is all you need.

Download the app See how the practice works
The app mid-session during the first full breath, showing the live breath training zone and this round's goal
Drs. Ed Reuvers today

The question behind the project

Why This Exists

Eighteen years of teaching Buteyko breathing left me with a question. Early on I taught the strongest version of the method. It provided the best results, but many people found it too intense to sustain long-term. I adapted the approach to give people more control over their own intensity and encouraged lower intensity for better long-term results. But the question stayed open: if the strongest version works best, is there a way to make it easier to do and easier to teach?

Over the last ten years, I took an increasingly experimental attitude to the practice. I was particularly interested in ways that allow effective training while measuring how the training impacts body and mind. Achieving this required changes to the exercises that went beyond the Buteyko framework and were inspired by pranayama and Tummo.

That also required a new app: new exercise flows, a wider selection of variants, a walking version, and sensor-free stress detection that finds the right intensity for you. Zones show your position in real time and tell you whether a breath-hold was right or too strong. Relaxation is at the center of the design, because the deeper you relax, the better you perform.

The Origin Story The Science

Start with the free Foundation Course.

Free

Foundation Course

Sign up and your course starts. Go at your own pace in the app. Join the Foundation Weekend to go deeper with an instructor.

Free Foundation Course

Follow-up Courses

After Foundation, continue with the Immersion and Summit courses. Or join a live weekend event.

Courses, events and coaching
Instructor training Contact us

12

Exercise Styles

  • Intro, Feather, Soft, Soft+,
  • Medium, Medium+, Strong, Strong+,
  • Extreme, Extreme+, Complete, Walking

100+

Combinations

  • 14 levels per style:
  • Levels 1–13 plus
  • recovery level

You set the direction: a level and style your body can handle and your mind enjoys. From there, the app handles the moment to moment, setting and adjusting your targets as you progress through the session.

What's Different

Traditional exercises to improve oxygen efficiency have four limitations. We resolve all four.

Problem 1: Years-long preparation

In the classical lineages of yoga and Tummo, years of preparatory practice are required before accessing the most effective breathing exercises.

Solution 1: Start today.

Our program is designed so you can start practicing and get results from day one. Most people notice real changes within 60 days.

Problem 2: Instructor dependency

Results depend on having a highly skilled teacher. But it takes years and thousands of students to become one.

Solution 2: The app knows how you breathe.

It guides you directly, round by round. Instructors use the same reading.

Problem 3: No stress detection

Intense breathing exercises can create subtle forms of tension and emotion without you realizing it.

Solution 3: See your stress in real time.

The app shows your nervous system state in real time, helping you relax deeper.

Problem 4: One size fits all

One intensity for everyone doesn't work. For some it is too low, for others it is too high.

Solution 4: The exercise adapts to you.

You choose your level and style, and the app adapts the exercise to how you perform and how relaxed you are.

Free Foundation Course
See how the practice works How it compares to Pranayama, Buteyko, and Tummo How it reads your nervous system

Oxygen Efficiency: The Science

Oxygen efficiency training is backed by decades of research. These are the results.

7–8s

Faster per km after breath-hold training

+24%

EPO production after repeated breath-holds

60%

More efficient CO₂ response when trained

VO₂max

Better running economy with nasal breathing

+9.5%

Hemoglobin after breath-hold diving

+30.5%

Longer breath-hold from training

Learn more

Go Deeper

Learn more about oxygen efficiency and how your nervous system responds.

More Oxygen from Less Air

How CO2 tolerance and minute volume work together to improve oxygen efficiency and clear the oxygen traffic jam.

Learn more →

The Nervous System

How the instinct and intellect share control of the breath, and how the app detects your nervous system state to score your breathing and adapt exercise intensity.

Learn more →

Meet Our Instructors

Certified instructors ready to guide your breathing practice.

Upcoming Events

Programs run throughout the year. Start free, then progress through the stages at your own pace.

View all →

Common Questions

Here are answers to common questions about the Reuvers™ program.

What does this practice do for me?
You sit down, follow a guided round on your phone, and over weeks your breathing becomes quieter and more efficient. After a few days or weeks, you start to notice the difference: more energy, more calm, and more stamina. The energy comes from drawing more oxygen out of less air, so the same work costs you less than it used to. The calm follows the long, slow exhale, which lowers tension while you practice and brings down your background stress level over the weeks, not only the spikes. The stamina shows in movement, where you stop running out of breath as early. Underneath, the training works on what your whole body runs on: how well your blood delivers oxygen, how steady your acid-base balance stays, and how calm your nervous system is. Breathing is a lifestyle factor in the way diet, exercise, and meditation are, and it is the one most people leave out. As those foundations improve, much that depends on them improves too, often without your aiming at it directly. Regular exercise works the same way: it raises your general condition, and the improvements follow.

What results can I expect?
The changes build over weeks rather than arriving at once. What you notice first is usually the practice itself getting easier: your breath-holds lengthen while staying comfortable, and the breath after them stays soft. Sleep improves as calmer breathing carries into the night. Once the mind is quiet, focus holds for longer. In movement you sustain the same effort on noticeably less air. How much of this you feel depends on how consistently you practice. Individual results vary. The studies are on our research page.

Why does it work?
Feather breathing brings your breath right down. The big breaths open it all the way up, briskly, which works the breathing muscles through their full movement. Then the breath-hold goes the other way again. Round after round your breathing moves from one side to the other, and that movement is itself part of the training: your body adapts to working across the whole range rather than to one fixed setting. The breath-holds train you to draw more oxygen from less air. The full breaths build respiratory strength, and in one trial twelve weeks of breathing exercises alone brought people's inspiratory strength up into the normal predicted range. Nose breathing carries your own nitric oxide into the lungs, where it opens blood vessels and helps oxygen pass into the blood, and a humming exhale raises that output up to fifteenfold. Slowing the breath reaches your nervous system directly. It lines your breathing up with your heart's own rhythm and shifts the balance toward the calming side. Slower again, at around three breaths a minute, that effect is stronger still. The contemplation that closes each round keeps you in that calm rather than letting it go. Underneath all of it, calm and trained breathing keeps your acid-base balance steady, which is the environment your enzymes work best in.

Why does breathing less give you more oxygen?
When you breathe more than your body needs, your blood holds onto its oxygen more tightly, delivering less to your cells. Breathing less allows your blood to release more oxygen where it's needed. More oxygen from less air. The mechanism behind this is CO₂ tolerance. When you breathe less or hold your breath, your CO₂ tolerance increases. This triggers your blood to release more oxygen to your cells. The physiology behind this is called the Bohr effect, and it's been in every physiology textbook since 1904. "Oxygen efficiency" is what you experience. CO₂ tolerance is how it works. The exercises train both. This is the reason targeted breathing training produces much larger effects than generic breathing exercises.

Is there scientific evidence?
Yes, and it covers more than breathing mechanics. The research page groups published studies by theme: oxygen delivery and nasal breathing, the nervous system and emotion, stress and anxiety, heart rate variability, focus and attention, sports performance, respiratory muscle strength, sleep, and cellular protection. One systematic review of breathing therapy for anxiety pooled 40 randomised trials and more than 3000 participants. Another pooled 10 trials measuring markers of oxidative stress. Full citations and study details are on our research page.

What makes this different from other breathing apps?
Mechanism. Most breathing apps guide you to breathe slowly. That helps, but research shows the effect is small. This app trains slow breathing too, and adds breath-holds and full, brisk big breaths that open your breathing all the way up. Together they produce much larger effects. The app uses sensor-free stress detection to find your optimal intensity, the level where training is most effective without triggering a stress response. No equipment needed. Your breath training zone shows where you are in real time, and the app adapts each round. The 30-day program adds expert instructor support for those who want guidance at higher intensities.

How does the app optimize my practice?
The app guides you from start to finish of each session, recording your scores, tracking durations of each stage, and helping you stay in the optimal breath training zone. It monitors your zones during each round and gently guides you to avoid overexertion, automatically adjusting intensity as needed. Between sessions, the app shows your full history with detailed progress charts, tracks your practice momentum, and reminds you when it's time to practice again. This helps you build strength confidently, stay consistent, and avoid common mistakes.

Is this suitable for beginners?
Yes, it's ideal for beginners. The app uses breath training zones to automatically guide your intensity, making it simpler and smoother to train effectively. Our structured program with instructor support helps you avoid common mistakes, and our instructors offer personalized guidance and answer your questions as you learn. You'll build confidence in your practice and develop your breath training skills gradually.

Are there any side effects?
Some people experience temporary adjustment symptoms as their breathing patterns change. Our gradual learning program with instructors helps you prevent or manage these effects by adjusting exercise intensity as needed. If you experience symptoms like elevated heart rate, headache, or feeling unwell, lower your exercise level, practice more gently and avoid pushing. Breath training zones help here as they monitor your intensity in real time, so you can ease up before pushing too hard. But common sense still applies. Always consult your doctor if you have concerns. Always stop the exercise immediately and seek medical attention if you experience chest pain, severe dizziness, fainting, or any concerning symptoms during practice or immediately after. Always practice seated somewhere safe. Never do the breath-holds in or near water, or while driving or operating machinery.

How often should I do the exercise?
For best results, do 1 to 3 sessions per day during the course, totalling at least 12 rounds per day (about 30 mins). Over the long term you can do less to maintain your progress. Users can make faster progress and experience better results by doing 25 to 35 rounds per day, but this may increase the risk of side-effects. While this is recommended for some, it is not suitable for all. Your breath training zones help you gauge whether your current frequency and intensity are sustainable. Our instructors can help you further optimize the approach for your needs.

How do I know I'm making progress?
You're making progress if your scores are improving while staying in the same breath training zone, the exercises are interesting and enjoyable and your practice feels smoother over time. You may also notice better health, wellness, and fitness, with your overall well-being improving. Aim for genuine growth and sustainable, long-term results.

Are there any conditions I should be aware of before starting?
If you have asthma, hypertension, heart conditions, migraine, diabetes, COPD, epilepsy, anxiety, panic disorders or other chronic issues, start with SOFT INTRO level and avoid MEDIUM and STRONG levels. The 30-day program with an instructor is highly recommended for personalized safety guidance. If SOFT INTRO feels fine, you can try higher soft levels gradually, but always listen to your body and consult your doctor. Don't force breath-hold intensity if it increases symptoms or causes physical discomfort. Also see the contraindications section in the full FAQ for more details.

Contraindications: Who should NOT do the exercise?
Do NOT practice these exercises if you are in the second half of pregnancy, have had recent major surgery, recently had a heart attack or stroke, or have COPD / emphysema with elevated blood CO₂ levels.
View Full FAQ

Stay Connected

Breathing practice insights, program updates, and what we're learning from the research.

How Does This Help You?

What it adds, practice by practice.

Breathwork practitioners

It scores your breath-hold length and your recovery breath. Push too hard, and it shows.

Endurance athletes

One session trains respiratory strength, CO2 tolerance, and pattern. Your recovery breath gets scored.

Strength athletes

Trains the gas tank so you don't gas out. Each round of the session scores your recovery.

Mind-body & somatic practice

We steer you toward rest and recovery. Each round scores it.

Meditators

Graded holds shape the breath toward that quiet state. Actively, not just observed.

Yoga & pranayama

Breath retention and humming carry into the round. It adds a scored recovery breath.

Freedivers

A dry, land-based round that trains CO2 tolerance and scores the calm of your recovery breath.

Biohackers

One scored protocol covers CO2 tolerance, breath-holds, and HRV recovery. No wearable needed.

Ready to start?

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